The research project proposed will study the effects of cocaine abuse in HIV-infected individuals on neuropsychological functioning. Both HIV- infection and chronic cocaine abuse have been shown to impair such functioning. While there have been several studies concerning the general issue of substance abuse on cognitive status in HIV infection, no studies have specifically determined the potential additional adverse impact of cocaine abuse in this disease. Two groups of symptomatic HIV-infected individuals (cocaine abusers and non-drug abusers) will be administered neuropsychological tests, a detailed drug history interview and several psychosocial measures. These groups will also be compared to a group of non-HIV-infected chronic cocaine abusers administered the same measures derived from a study by the co-PI's and the study's PI, Dr. Tony Strickland, presently nearing completion. Specific aims are: (1) To identify potentially greater deficits among HIV-infected individuals in neuropsychological functioning as a function of cocaine abuse; (2) To determine how parameters of cocaine use (e.g. lifetime exposure. peak use) influence neuropsychological and psychosocial (e.g. coping, anxiety, depression) functioning beyond that seen with HIV-infection without cocaine abuse. The following hypotheses will be tested: (1) cocaine abuse represents an added risk to neuropsychological functioning above and beyond that associated with HIV infection with measures of attention, concentration and memory expected to be most affected among the cognitive domains; (2) this added risk will be associated with the degree of cocaine exposure and the intensity of its use; (3) cocaine abuse more adversely affects psychosocial functioning among HIV-infected individuals and that this effect will be correlated with severity of cocaine abuse; (4) HIV- infected cocaine abusers will show greater neuropsychological impairment than seronegative cocaine abusers. The proposed study will significantly improve our knowledge of the potential additive or multiplicative effects of HIV-infection and cocaine abuse on cognitive functioning. Also, the project will generate new information concerning the demographic, psychosocial and drug use patterns that influence these neuropsychological effects. Such data will be invaluable in directing further research in this area including future efforts at tracking the longitudinal course of these patients and in maximizing the effectiveness of treatment of comorbid HIV infection and cocaine abuse.